This chapter describes the concept of investment and the items in an investment policy statement. Investment is the purchase of a financial or real asset by an individual, an organization, or an institution, in order to generate a return over time, which is proportional to the risk assumed during the investment period. The chapter identifies the different types of investments available for nonprofit organizations. The most common types of investments are short-term investment vehicles and fixed-income securities. Contrary to short-term investments, long-term investments are made with funds that are not needed for use in a period of less than a year. Examples of long-term investments are pension funds, self-insurance funds, and endowment funds. The chapter explains the extent to which investments can contribute to financial sustainability of nonprofit organizations. It summarizes the key principles for investment management and examines the management structures involved in investment for nonprofit organizations.